Moleculin calls first-45-patient MIRACLE results positive but gives no figures

Moleculin Biotech, Inc. (Nasdaq: MBRX) announced what it called positive preliminary unblinded efficacy results from the first 45 patients enrolled in Part A of its pivotal Phase 2/3 MIRACLE trial. The announcement was made in a press release dated June 30, 2026, filed as Exhibit 99.1 to a Form 8-K. The company said the analysis used a full intent-to-treat basis with no patient exclusions. Both Annamycin treatment arms showed favorable efficacy trends compared with the control arm in patients with relapsed or refractory acute myeloid leukemia (R/R AML).

The trial

The MIRACLE trial is designed to evaluate Annamycin in combination with cytarabine for R/R AML. The company's annual report describes the trial's name as derived from Moleculin R/R AML AnnAraC Clinical Evaluation. The annual report says the company had shown promising blinded safety and efficacy data for the first 30 subjects treated in the trial. It also said it expected an interim unblinding of efficacy data for the first 45 subjects in Part A in mid-2026, which is the analysis the June 30 release covers.

The annual report says the trial is pivotal and registration enabling, and that the company believes such early visibility is unique for a pivotal trial, because stakeholders receive preliminary safety and efficacy data well before the trial concludes.

The lead candidate

Annamycin, also called L-Annamycin and by its generic name naxtarubicin, is the company's lead drug candidate. The annual report describes it as a next-generation anthracycline and the first of its kind DNA binding agent. Earlier anthracyclines are used to treat approximately half of all cancers, but the company says they carry dangerous cardiotoxicity and limits from multidrug resistance and poor tissue distribution. The annual report says Annamycin uses a multilamellar lipid-based delivery system designed to improve bioavailability and widen the therapeutic window.

The company says five clinical trials of Annamycin, with 90 patients, showed it to be non-cardiotoxic, and that it exhibits no vesicant activity. Among second-line patients with R/R AML treated with cytarabine, the company reports a complete remission rate of 50% and a composite complete remission rate of 60%, in 10 subjects. The company also says it has shown encouraging activity in five different clinical trials, most of which are now complete, including relapsed and refractory AML with complete remission rates significantly above currently approved second-line therapies.

Financial position

The company reported no revenue for 2025 or 2024. Research and development expense was $15.9 million in 2025 and $17.7 million in 2024. The net loss was $33.6 million in 2025 and $26.0 million in 2024. Cash from operations was negative $22.7 million in 2025 and negative $23.9 million in 2024. Year-end cash and cash equivalents were $4.3 million at December 31, 2024, according to the company's XBRL data.

What the announcement leaves out

The 8-K carries no numbers. It gives no response rates, no remission figures for either Annamycin arm or the control arm, no p-values and no safety data, and "favorable efficacy trends" is the company's own description. The patients are 45 of a larger Part A, in an unblinded interim look, so the result can change as more patients are counted. The annual report's remission rates come from just 10 subjects in earlier trials, and a claim of rates significantly above approved second-line therapies rests on that small base. The company used $22.7 million of operating cash in 2025 and lost $33.6 million. Its own report expected a further unblinding in the second half of 2026 before Part A concludes.

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